SERVER-70424: Provide way to create collection instance from untimestamped storage snapshot

1 files changed, 44 insertions, 0 deletions

diff --git a/src/mongo/db/catalog/collection_catalog_test.cpp b/src/mongo/db/catalog/collection_catalog_test.cpp
index 8710d807f73..7782e58e855 100644
--- a/src/mongo/db/catalog/collection_catalog_test.cpp
+++ b/src/mongo/db/catalog/collection_catalog_test.cpp
@@ -2388,5 +2388,49 @@ DEATH_TEST_F(CollectionCatalogTimestampTest, OpenCollectionInWriteUnitOfWork, "i
         CollectionCatalog::get(opCtx.get())->openCollection(opCtx.get(), nss, readTimestamp);
 }
 
+TEST_F(CollectionCatalogTimestampTest, OpenCollectionNoTimestamp) {
+    RAIIServerParameterControllerForTest featureFlagController(
+        "featureFlagPointInTimeCatalogLookups", true);
+
+    const NamespaceString nss("a.b");
+    const Timestamp createCollectionTs = Timestamp(10, 10);
+    const Timestamp createIndexTs = Timestamp(20, 20);
+    const Timestamp readTimestamp = Timestamp(30, 30);
+
+    createCollection(opCtx.get(), nss, createCollectionTs);
+
+    // Fetch a collection instance after creation but before creating an index. Maintain a reference
+    // to the current catalog so the collection instance isn't invalidated when the snapshot is
+    // abandoned.
+    auto preIndexCatalog = CollectionCatalog::get(opCtx.get());
+    auto preIndexColl = preIndexCatalog->lookupCollectionByNamespace(opCtx.get(), nss);
+    ASSERT(preIndexColl);
+    ASSERT_EQ(0, preIndexColl->getIndexCatalog()->numIndexesTotal());
+
+    createIndex(opCtx.get(),
+                nss,
+                BSON("v" << 2 << "name"
+                         << "x_1"
+                         << "key" << BSON("x" << 1)),
+                createIndexTs);
+    OneOffRead oor(opCtx.get(), readTimestamp);
+    Lock::GlobalLock globalLock(opCtx.get(), MODE_IS);
+
+    // Open an instance of the latest collection by passing no timestamp.
+    auto coll = CollectionCatalog::get(opCtx.get())->openCollection(opCtx.get(), nss, boost::none);
+    ASSERT(coll);
+    ASSERT_EQ(1, coll->getIndexCatalog()->numIndexesTotal());
+
+    // Verify the CollectionCatalog returns the latest collection.
+    auto currentColl =
+        CollectionCatalog::get(opCtx.get())->lookupCollectionByNamespace(opCtx.get(), nss);
+    ASSERT(currentColl);
+    ASSERT_EQ(1, currentColl->getIndexCatalog()->numIndexesTotal());
+    ASSERT_EQ(coll, currentColl);
+    ASSERT_NE(coll, preIndexColl);
+
+    // Ensure the idents are shared between the up-to-date instances.
+    ASSERT_EQ(coll->getSharedIdent(), currentColl->getSharedIdent());
+}
 }  // namespace
 }  // namespace mongo